JPH0727310B2 - Document size detection device for movable copy machines - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a document size detecting device of a document platen moving type copying machine which travels a document platen and makes a copy.

(Prior Art) Conventionally, in a fixed copyboard type copying machine, control such as automatic cassette selection or automatic magnification setting is performed. There is a device in which the size of a document is detected by irradiating a document with light from an installed light emitting device and detecting the presence or absence of the reflected light by light receiving devices provided at a plurality of locations. That is, the reflected light is detected by the light receiving devices respectively arranged at the positions corresponding to the size of the original to be used, and the size of the original is detected by the combination of the light receiving states of the respective light receiving devices.

On the other hand, in the platen moving type copying machine, since the platen is configured to be movable, its position is not constant, and the stop position is not always specified even when the platen is stopped. As described above, in the document table moving type copying machine, since the position of the document table is not specified, the document size detecting means is apt to malfunction, and it is difficult to accurately detect the document size. It was

(Object of the Invention) The present invention has been made in order to solve the above-mentioned problems, and detects a document size accurately and quickly with a simple configuration in a document table moving type copying machine without malfunction. The purpose of the present invention is to obtain a document size detecting device that can be used.

(Structure of the Invention) A document size detecting device of the present invention is a document platen moving type copying machine that travels a document platen to make a copy, and a document size detecting unit for detecting a rear end position of a document placed on the document platen. A document table detecting means for detecting that the document table is located at a reference position provided between a home position and an exposure start position is provided below the document table, and is output from the document table detecting means. Control means for outputting an operation signal to the original size detecting means in response to the detection signal, and when the original table reaches the reference position, the original size detecting means is operated to detect the trailing edge position of the original. The document size is thus detected.

With this configuration, the document size detecting means is activated when it is detected that the document table is at the reference position, and the size of the document at the reference position can be accurately detected.

(Embodiment) FIG. 1 is a schematic diagram of a document table moving type copying machine. A document table 2 provided with a contact glass 2a on which a document D is placed is installed above a machine body 1 of this copying machine so as to be movable in the left-right direction in the drawing. A paper feed cassette 3 accommodating copy papers of different sizes is attached to the machine body 1, and the copy papers fed from the paper feed cassette 3 through a paper feed roller 4 are guided by guides 5 and registration rollers. 6, it is configured to be supplied to the transfer portion of the photosensitive drum 8 via the pre-transfer roller 7.

Above the photoconductor drum 8, an exposure lamp 9 for irradiating the original D with light, mirrors M ₁ , M ₂ , M ₃ , M ₄ for guiding the reflected light from the original D, and a lens L ₁ are provided. An optical system section 10 is provided. In addition, in the peripheral portion of the photosensitive drum 8,
A main charger 11 for uniformly charging the drum surface, a developing device 13 provided with a developing roller 12, a transfer charger 14 and a separating claw.
A cleaning device 16 and a cleaning device 16 are sequentially arranged in the rotation direction of the photosensitive drum 8. The copy paper led out from the transfer portion of the photoconductor drum 8 is supplied to the fixing roller 18 via the transport mechanism 17, and is then drawn out onto the paper discharge tray 20 by the discharge roller 19. There is.

Further, the original table 2 is moved from the initial stop position (home position) shown by the solid line in FIG. 1 to the right in the drawing, and the tip of the contact glass 2a (the left end in the drawing) is the exposure lamp 9. The exposure start positions are set to face each other. afterwards,
By moving the document table 2 to the left in the drawing in accordance with the rotation of the photoconductor drum 8, the image of the document table D is exposed on the photoconductor drum 8 by the optical system section 10.

Further, a document table detecting means 21 composed of a photo sensor is arranged below the front end of the document table D.
21 is configured to detect that the document table 2 is at a reference position, that is, a position slightly moved to the right from the pom position. That is, as shown in FIG. 2, the white portion 23a is formed on the lower surface of the peripheral portion of the contact glass 2a.
When the document table 2 is attached to the reference position display plate 23 including a black portion 23b on the periphery of the white portion 23a, the light emitted from the light emitting portion 21a of the photosensor is reflected by the white portion 23a. When the reflected light is incident on the light receiving portion 21b, it is detected that the document table 2 is at the reference position.

Below the document table 2, a plurality of photosensors 24a,
A document size detecting means 24 composed of 24b and 24c is provided, and when the document table 2 is at the reference position, the document D is detected.
Is configured to detect the size of the. That is,
The photosensors 24a, 24b, 24c are arranged at positions corresponding to the rear end portions of the documents D of various sizes (B5, A4, B4, etc.) at the reference position, and the document table detecting means 21.
When a detection signal is input from the control unit 25 to the control unit 25, the control unit 25 operates based on the operation signal output from the control unit 25, and the size of the document D is detected by detecting the rear end position of the document D. Is configured.

In the above configuration, when the copy start button is pressed after the document D of a predetermined size is placed on the document table 2, the document table 2 starts moving from the home position toward the exposure start position, and the document table is moved during the movement. When 2 reaches the reference position, the platen detector 21 detects the white portion 23a of the reference position display plate 23, and the platen detector 21 controls the controller 2
A detection signal is input to 5 and an operation signal is output from the control means 25 to the document size detection means 24. As a result, when the document table 2 is at the reference position, the size of the document D at the reference position can be accurately detected by the detection means 25. That is, since the size of the document D is detected while the position of the document table 2 is predetermined by the document table detecting means 21 and the reference position display plate 23, malfunction can be prevented. Then, the size of the copy paper to be used can be calculated based on the original size detection signal and the copy magnification setting signal, and the copy paper of the corresponding size can be automatically supplied from the paper feed cassette 3.

In the above embodiment, the reference position display plate 23 is provided directly on the lower surface of the contact glass 2a, but it may be directly attached to the lower surface of the frame plate 22 for displaying the original placement position, or on the lower surface of the original holder. The structure may be attached. Further, the reference position for operating the document size detecting means 24 is not limited to the above position, but may be changed to various positions such as the exposure start position and its vicinity, except the position after the exposure operation is started. Further, as the document table detecting means 21 for detecting the reference position, another sensor such as a limit switch can be used instead of the photo sensor.

(Advantages of the Invention) As described above, according to the present invention, the document size detecting means is activated at the time when the document table detecting means detects that the document table is at the reference position. In the copy table moving type copying machine configured as described above, it is possible to accurately detect the size of the copy with the position of the copy plate specified. The original size is detected by the original size detecting means arranged below the original plate while the original plate moves from the home position to the exposure start position at the start of copying. If the document size detecting means is provided in the document table, the thickness of the document table becomes large, or the structure becomes complicated as when the document size detecting means is movably provided below the document table. There is an advantage that the size of the document can be accurately and quickly detected with a simple configuration without causing a problem such as the occurrence of the problem.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view of a contact glass. 2 ... original table, 21 ... original table detecting means, 23 ... reference position display plate, 24 ... original size detecting means, 24a, 24b, 24c.
Photo sensor, 25 ... Control means.

Claims (1)

[Claims] 1. A manuscript table moving type copying machine for moving a manuscript table to make a copy, and a manuscript size detecting means for detecting a trailing end position of a manuscript placed on the manuscript table, the manuscript table and a home position and exposure. Document platen detection means for detecting that the document platen is located at a reference position provided between the start position and the start position is provided below the document platen, and the document size is determined according to a detection signal output from the document platen detection means. The detection means is provided with control means for outputting an operation signal, and when the document table reaches the reference position, the document size detection means is operated to detect the rear end position of the document to detect the document size. A document size detecting device for a movable copy machine of a document table characterized by being configured.